SeaSea Hares (Reef Safe): The Rabbit of the Ocean World

By Hannah Henegar

sea hares

Sea Hares

Sea hares, clade Aplysiomorpha, are medium-sized to very large Opisthobranchia with a soft internal shell made of protein. These are marine gastropod molluscs. The common name “sea hare” is direct translation from Latin lepus marinus, as the animal’s existence was known in Roman times. The name derives from their rounded shape and from the two long rhinophores that project upwards from their heads and that somewhat resemble the ears of a hare.

Sea hares are mostly rather large, bulky creatures when adults. Juveniles are mainly unobserved on the shoreline. The biggest species can reach a length of 30 inches and a weight of 31 lbs and is arguably the largest gastropod species. Sea hares have soft bodies with an internal shell, and like all other molluscs, they are hermaphroditic. Unlike many other gastropods, they are more or less bilaterally symmetrical in their external appearance. The foot has lateral projections, or “parapodia”.

Life habits

Sea hares are herbivorous, and are typically found on seaweed in shallow water. Some young sea hares seemingly are capable of burrowing in soft sediment, leaving only their rhinophores and mantle opening showing. Sea hares have an extremely good sense of smell. They can follow even the faintest scent using their rhinophores, which are extremely sensitive chemoreceptors. Their color corresponds with the color of the seaweed they eat: red sea hares have been feeding on red seaweed. This camouflages them from predators. When disturbed, a sea hare can release ink from its ink glands, providing a fluid, smoke-like toxic screen, adversely affecting its predators’ olfactory senses while acting as a powerful deterrent. The toxic ink may be white, purple, or red, depending on the pigments in their seaweed food source and lightens in color as it spreads, diluted by seawater. Their skin contains a similar toxin that renders sea hares largely inedible to many predators.

Some sea hares can employ jet propulsion as a way of movement and others move like a stingray but with greater fluttering fluidity in their jelly-like “wings”. In the moving marine environment and without the sophisticated cognitive machinery of the cephalopods, their motion appears to be somewhat erratic, but they do reach their goals, such as the seabed, according to the wave-action, currents, or calmness of their area.

Reef Aquaria

Sea hares are often used as a method of eradicating nuisance algae and cyanobacteria (“red slime algae”) in reef aquaria. The hares usually do an excellent job, but when they have eaten all of the algae and cyanobacteria, they often shrink from starvation and eventually starve to death. Many reef-keeping clubs have started programs where groups of hobbyists “share” a single sea hare among a large group.

Lettuce Nudibranch

The Lettuce Nudibranch is a very interesting and useful creature. Nudibranch for sale: they are in very high demand but quite inexpensive. It helps tackling the unnecessary growth of algae. The Lettuce Nudibranch destroys and eliminates the growth of algae by foraging on live rocks and aquarium glass. Thus, it helps keeping the environment clean and clear. It is non venomous and a very hardy species, which makes it a terrific addition to any reef tanks. The Lettuce Nudibranch is photosynthetic in nature, and gets benefits from the chloroplast in their tissue from the algae they eat. It sucks in the chlorophyll contents of algae, and then incorporates that chlorophyll into their own tissues. The Lettuce Nudibranch is closely reassembled to a lettuce leaf, which is why it is named the Lettuce Nudibranch. It reaches a maximum size of 3 inch and is very hardy. The Lettuce Nudibranch is passive in nature, and is more active during daytime and less at night time. There are no distinctive features that differentiates male from, female. The reef tank should be maintained with 70-80 degrees Fahrenheit for the proper growth and development of the Lettuce Nudibranch. It is a bright green color with ruffles across its back. It has an elongated oval shaped body and due to presence of ruffles it increases its surface area in order to absorb more oxygen for respiration. The aquarium needs to have some live rocks which serve as a natural shelter for the Lettuce Nudibranch. They belong to Gastropods class who are snail like creature and do not possess any shell for their protection. The Lettuce Nudibranch is very peace loving and gets along with other inhabitants. It surely makes the aquarium more attractive with its interesting appearance and function.

California Sea Hare

The California brown sea hare, a mollusk, is also called a sea slug. It is a marine snail that has an interior small remnant of a shell and no external shell. The common name, sea hare, is derived from the large anterior tentacles that are ear-like and were thought by some to resemble the ears of a hare. This species “inks”, that is, expels a thick cloud of purple ink.California brown sea hares have two pairs of tentacles on the top of the head, one pair near the mouth and the other behind the eyes. The anterior are an aid in locomotion, and the posterior are used for smelling. The mantle, which covers the gills, has external wing-like extensions that extend almost the entire length of the animal’s body, up over each side of the back meeting at or close to the center. These extensions are called parapodia. The color of these sea hares is dependent on the color of algae that they eat. Coloration ranges from reddish-brown to greenish-brown with some mottling.

The California black sea hare, Aplysia vaccaria, is the largest gastropod in the world. It can grow to be as long as 75 cm (29 in) in length with a weight of up to 13.6 kg (30 lb). Unlike the California brown sea hare, it does not eject ink.

Most sea hare species expel a cloud of purple ink, a behavior similar to that of their more advanced inking relatives, octopus and squid. Some scientists believe this is an evolutionary link among these mollusks, none of which have an external shell.